1. The crafted level 50 PvP-gear is faaar to superior to your normal gear, and honestly you dont even need PvP-gear in most PvP. Your best PvE-gear is totally fine!

2. The Feast (and Fold) is purely PvP, frontlines has PvE-elements aswell and people might even focus on them. Please note that as a healer you can not use cleric stance so your damage-contribution is a lot lower than in PvE

3. Wear some tank-jewls to buff your HP - getting above 10k HP allows you to survive melee-LBs and the loss in healing and MP is totally fine. Make yourself familiar with your PvP-skills, there are some real lifesafers amongst them! (As a whm people will hate you for using fluid aura, but since you battle them, its okay that they hate you!) Healing can get pretty hectic, too, so dont be discouraged if you need a few games to get into it!